Three-Dimensional Wireless Power Transfer System Using Multiple Orthogonal Resonators for Spatial Freedom

In this article, the 3-D wireless power transfer (WPT) system using multiple orthogonal resonators for spatial freedom is proposed. The proposed transmitter comprises three orthogonal resonators with a 3-D structure. The three orthogonal resonators are positioned on top and bottom of the substrate, and the proposed system has an open box-shaped structure due to the 3-D resonators. The proposed WPT system allows power transfer despite the receiver’s lateral and angular misalignments by generating magnetic fields in all directions generated by multiple resonators. For performance verification, the operating principle of the proposed WPT system is theoretically calculated and simulated. Also, the power transfer efficiency (PTE) under the lateral and angular misalignments is measured and compared with the conventional WPT system and the WPT system implemented on the 2-D plane using multiple orthogonal resonators. The proposed WPT system achieves a PTE from 46.8% to 71.6% when the receiving resonator is set to81 × 51mm2, which can be built into the mobile phone, and the charging volume is201 × 201\,\,×51mm3.